Pentagon leaders on Wednesday stressed the importance of diplomacy in the fight against the Islamic State but sidestepped questions from Senate appropriators about the Trump administration’s proposed 29 percent cut to the State Department and other foreign operations accounts in fiscal 2018.

Defense Secretary James Mattis and Joint Chiefs of Staff Chairman Gen. Joseph Dunford pitched lawmakers on the military’s $30 billion request for supplemental funding for fiscal 2017, as well as the planned $54 billion boost to defense accounts proposed for next year, arguing that military readiness has been depleted after 16 years of war.

“The bottom line is, America can afford survival,” Mattis told the Senate Defense Appropriations Subcommittee, adding that the military “can’t do it on the cheap.”

Several panel members, however, pushed Mattis and Dunford on the sizeable State Department cut the White House has put on the table to help pay for the hefty defense boost. The proposal is unpopular with members of both parties, including GOP defense hawks who welcome the bigger Pentagon budget.

Mattis emphasized his close working relationship with Secretary of State Rex Tillerson, who he said he speaks to three to four times a week. The retired four-star general said he planned to spend Wednesday afternoon in Foggy Bottom at a meeting that Tillerson called with representatives from 68 countries on the international strategy against ISIS.

The United States, Mattis added, has two tools to defeat the terrorist organization: the power of intimidation and the power of inspiration.

“Soft power is largely found in the power of inspiration and [is] part and parcel with how we defeat this enemy,” he said.

Dunford noted that there are nine areas the United States has identified as critical to the current strategy against ISIS, and the Defense Department leads only two of those areas

“It is important for us to leverage all the capabilities our nation has,” Dunford said.

But while both men advocated for diplomacy, they stuck largely to their key mission: to push for the fiscal 2017 supplemental spending request, which includes $5.1 billion for ongoing operations overseas and another $24.9 billion in base-budget items like aircraft.

Democrats have balked at the proposal because the additional base-budget funding ignores the spending caps in place for this fiscal year. To offset the defense increase, the administration has proposed $18 billion in fiscal 2017 cuts elsewhere in the government but has not specified where.

“We all know what’s on the chopping block,” Senate Defense Appropriations ranking member Richard J. Durbin, D-Ill., said. “The White House is already proposing extremely reckless cuts to agencies like the State Department for the next year, which would jeopardize our nation’s ability to deal with crises without resorting to arms.“

The supplemental, the Pentagon leaders said, would allow the military to replace worn-out aircraft and other equipment, maintain other gear and improve overall force readiness. Mattis called it the first step in a years-long plan to narrow the readiness gap in the military, a problem he called severe.

“In my role, to keep the president and the secretary of State and our diplomats always negotiating from a position of strength is an obligation that I carry,” Mattis said.